50A56-956
Integrated Furnace Control
INSTALLATION INSTRUCTIONS
FAILURETO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL INJURY AND/OR PROPERTY DAMAGE.
The 50A56-956 is an automatic gas interrupted ignition control that employs a microprocessor to continually monitor, analyze, and control the proper operation of the gas burner, inducer, and fan.
Signalsinterpretedduringcontinualsurveillanceofthethermostat and flame sensing element initiate automatic ignition of the burner, sensing of the flame, and system shut-off during normal operation.
These controls incorporate system fault analysis for quick gas flow shut-off, coupled with automatic ignition retry upon sensing a fault correction.
Kit includes: 1) |
Ignition Control 2) Metal Control Box |
3) |
Install Sheet |
DESCRIPTION
50A56-956 Cross Reference Information
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York |
White-Rodgers |
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S1-33102956000 |
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S1-03101266000 |
50A56-242 |
S1-03109167000 |
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S1-03101284000 |
50A56-243 |
S1-03101933000 |
S1-03101973000 |
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S1-03101267000 |
S1-03101972000 |
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S1-03101267001 |
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265901 |
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S1-03100662000 |
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265902 |
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S1-03101250000 |
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539617 |
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S1-33103010000 |
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PRECAUTIONS
Installation should be done by a qualified heating and air conditioning contractor or licensed electrician.
Ifindoubtaboutwhether your wiring ismillivolt,line, or lowvoltage, have it inspected by a qualified heating and air conditioning contractor or licensed electrician.
Do not exceed the specification ratings.
All wiring must conform to local and national electrical codes and ordinances.
This control is a precision instrument, and should be handled carefully. Rough handling or distorting components could cause the control to malfunction.
Following installation or replacement, follow manufacturer’s recommended installation/service instructions to ensure proper operation.
! CAUTION
Do not short out terminals on gas valve or primary control. Short or incorrect wiring may damage the thermostat.
CONTENTS |
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Description ......................................................... |
1 |
Precautions ........................................................ |
1 |
Specifications ..................................................... |
2 |
Installation .......................................................... |
3 |
Mounting & Wiring |
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Operation ........................................................... |
6 |
Troubleshooting.................................................... |
8 |
! WARNING 
Failure to comply with the following warnings could result in personal injury or property damage.
FIRE HAZARD
•Do not exceed the specified voltage.
•Replace existing control with exact model and dash number.
•Protect the control from direct contact with water (dripping, spraying, rain, etc.).
•If the control has been in direct contact with water, replace the control.
•Label all wires before disconnection when servicing controls.Wiring errors can cause improper and dangerous operation.
•Route and secure wiring away from flame.
SHOCK HAZARD
•Disconnect electric power before servicing.
•Ensure proper earth grounding of appliance.
•Ensure proper connection of line neutral and line hot wires.
EXPLOSION HAZARD
•Shut off main gas to appliance until installation is complete.
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PART NO. 37-7475B |
www.white-rodgers.com |
Replaces 37-7475A |
www.emersonclimate.com |
1419 |
SPECIFICATIONS
ELECTRICAL RATINGS [@ 77°F (25°C)]: Input Voltage: 25 VAC 50/60 Hz
Max. Input Current @ 25 VAC: 0.45 amp Relay Load Ratings:
Valve Relay: 1.5 amp @ 25 VAC 50/60 Hz 0.6 pf Ignitor Relay: 6.0 amp @ 120 VAC 50/60 Hz (resistive) Inducer Relay: 2.2 FLA–3.5 LRA @ 120 VAC Circulator Relay: 14.5 FLA–25.0 LRA @ 120 VAC
Flame Current Requirements:
Minimum current to insure flame detection: 1 µa DC* Maximum current for non-detection: 0.1 µa DC* Maximum allowable leakage resistance: 100 M ohms
*Measured with a DC microammeter in the flame probe lead
OPERATINGTEMPERATURE RANGE:
-40° to 176°F (-40° to 80°C)
HUMIDITY RANGE:
5% to 93% relative humidity (non-condensing)
MOUNTING:
Surface mount multipoise |
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Timing Specs: (@ 60 Hz**) |
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maximum |
Flame Establishing Time: |
0.8 sec |
Flame Failure Response Time: |
2.0 sec |
Gases Approved: Natural, Manufactured, Mixed, Liquified Petroleum, and LP Gas Air Mixtures are all approved for use.
**At 50% Hz, all timing specifications should be increased by 20%
TIMING SPECIFICATIONS
(All times are in seconds, unless noted otherwise)
Event |
Definition |
50A56-956 |
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Pre-Purge |
The period of time intended to allow for the dissipation of any unburned |
0 |
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gas or residual products of combustion at the beginning of a furnace |
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operating cycle prior to initiating ignition |
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Trial for Ignition |
The period of time between initiation of gas flow and the action to |
7 |
Period (TFI) |
shut off the gas flow in the event of failure to establish proof of the |
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supervised ignition source or the supervised main burner flame. |
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Ignition Activation |
The period of time between energizing the main gas valve and |
5 |
Period (IAP) |
deactivation of the ignition means prior to the end of TFI |
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Retries |
The additional attempts within the same thermostat cycle for ignition |
2 times |
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when the supervised main burner flame is not proven within the first |
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trial for ignition period. |
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Recycles |
The additional attempts within the same thermostat cycle for ignition |
4 |
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after loss of the supervised ignition source or the supervised main |
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burner flame. |
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Valve Sequence |
Valve sequence period equals 7 seconds trial for ignition period x |
21 |
Period |
(1 initial try + 2 retries) + 12 seconds. |
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Interpurge |
The period of time intended to allow for the dissipation of any unburned |
15 |
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gas or residual products of combustion between the failed trial for |
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ignition and the retry period. |
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Post-Purge |
The period of time intended to allow for the dissipation of any unburned |
15 |
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gas or residual products of combustion at the end of a furnace burner |
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operating cycle. Post-purge begins at the loss of flame sense. |
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Lockout Time |
ANSI standard rated module timing. |
140 |
Heat Delay-To-Fan-On |
The period of time between proof of the supervised main burner flame |
30 |
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and the activation of the blower motor at Heat speed. |
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Heat Delay-To-Fan-Off* |
The period of time between the loss of a call for heat and the |
60/90/120*/180 |
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deactivation of the blower motor at Heat speed. |
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Cool Delay-To-Fan-On |
The period of time after a thermostat demand for cool before energizing |
0 |
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the circulator blower motor at Cool speed. |
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Cool Delay-To-Fan-Off* |
The period of time between the loss of a call for cool and the |
60 |
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deactivation of the blower motor at Cool speed. |
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Initial Ignitor Warm-up |
The length of time allowed for the igniter to heat up prior to the initiation |
17 |
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of gas flow. |
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Ignitor Warm-up Retries |
In the event of a retry, the warm-up time will be increased by one |
27 |
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second, up to a maximum of 27 seconds, and locked at that duration |
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Auto Reset |
After one (1) hour of internal or external lockout, the control will |
60 minutes |
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automatically reset itself and go into an auto restart purge for 60 seconds. |
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Electronic Air Cleaner |
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Yes |
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Humidifier |
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Yes |
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*This time will vary depending on option switch position. The control is factory set at 120 seconds HEAT delay-to-fan-off. See OPERATION section for further information
2
! WARNING 
Failure to comply with the following warnings could result in personal injury or property damage.
FIRE HAZARD
•Do not exceed the specified voltage.
•Replace existing control with exact model and dash number.
•Protect the control from direct contact with water (dripping, spraying, rain, etc.).
•If the control has been in direct contact with water, replace the control.
•Label all wires before disconnection when servicing controls.Wiring errors can cause improper and dangerous operation.
•Route and secure wiring away from flame.
SHOCK HAZARD
•Disconnect electric power before servicing.
•Ensure proper earth grounding of appliance.
•Ensure proper connection of line neutral and line hot wires.
EXPLOSION HAZARD
•Shut off main gas to appliance until installation is complete.
INSTALLATION
! CAUTION
Do not short out terminals on gas valve or primary control. Short or incorrect wiring may damage the thermostat.
MOUNTING AND WIRING
Certain upflow 90% models may require the installation of the provided metal control mounting box. The reuse of the existing door switch and transformer are required. Other models may require new mounting holes. In this case, use the mounting template located in figure 1. Specifically the BGU model furnaces may required not only new mounting holes, but also relocation of the existing transformer. In all cases the wiring connections will remain the same.
All wiring should be installed according to local and national electrical codes and ordinances.
The control must be secured to an area that will experience a minimum of vibration and remain below the maximum ambient temperature rating of 175°F. The control is approved for minimum ambient temperatures of -40°F.
Any orientation is acceptable.
Refer to the wiring diagram, page 4 and wiring table, page 5 when connecting the 50A56 control to other components of the system.
UL approved, 105°C rated 18 gauge, stranded, 2/64” thick insulation wire is recommended for all low voltage safety circuit connections.
UL approved 105°C rated 16 gauge min., stranded, 4/64” thick insulation wire is recommended for all line voltage connections.
After installation or replacement, follow appliance manufacturer’s recommended installation or service instructions to ensure proper operation.
3
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TYPICAL SYSTEM WIRING DIAGRAM |
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HOT |
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NEUTRAL |
(LINE) |
120 VAC |
(LINE) |
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24 VAC CLASS II |
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TRANSFORMER |
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TH |
24 VAC |
TR |
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50A56 |
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LO COOL |
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HI COOL |
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CIRCULATOR |
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HEAT |
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PARK |
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BLOWER |
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PARK |
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LINE |
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XFMR |
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EAC |
INDUCER |
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HUM |
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IND-N |
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IND |
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IGN |
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HUMIDIFIER |
IGN-N |
IGNITOR |
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CIR N |
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LINE N |
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XFMR N |
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ELECTRONIC |
HUM N |
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EAC N |
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AIR CLEANER |
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Y/Y2 |
Y/Y2 |
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W |
W |
COMPRESSOR |
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CONTACTOR |
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G |
G |
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50A56 |
R |
R |
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in other |
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furnace(s) |
C |
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— |
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TWINNING |
* Y1 |
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APPLICATIONS |
Y1 |
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ONLY |
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THERMOSTAT |
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TWIN |
TWIN |
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PRESSURE SWITCH (N. O.) |
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PS |
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HLI |
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HLO |
HIGH LIMIT |
AUX. HIGH |
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FLAME |
FP |
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(N. C.) |
LIMIT (N. C.) |
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SENSOR |
ROS |
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ROLLOUT |
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PROBE |
GND |
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(N. C.) |
GAS |
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ROSI |
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MV |
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VALVE |
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MV COM |
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TR |
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TH |
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LEGEND |
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Low Voltage (24 VAC) |
*For two stage cooling mode only |
Line Voltage (120 VAC)
N. C. = Normally closed switch
N. O. = Normally open switch
4
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